Physics 408 Spring 2003

How to Write Physics Lab Reports

There are three questions to keep in mind when writing lab reports.

• Could your friend (or your boss) read the report and understand exactly what you did?
• Could you read the report a month later and repeat the experiment and get the same results?
• Could another scientist read the abstract and immediately decide whether to take the time to read the full report? Every scientific article published has an abstract immediately under the title and author on the first page!

A full lab report consists of six parts.
You only do a full lab report for Lab #8. The short lab report still contains these elements, with less detail for sections II and III.

I. Abstract:
The abstract contains three things:

1. What you did.
2. How you did it.
3. The results obtained.

What you did means what you measured, including a very brief description of the apparatus.

How you did it, means the experimental procedures used, including the type of equipment.

Results mean the final numerical results including units and errors.

The abstract should generally be less than 200 words and appears at the top of the first page. You write the abstract only after the rest of the report is written. The abstract usually gives you an "overview" of the entire experiment and is often the most difficult part of the report to write.

II. Purpose & Theory:
The purpose is what you're trying to do.
The theory is a brief statement of the important equations and what you have to measure.

III. Procedure and Apparatus:
The procedure spells out the experimental steps you do in the lab.
The apparatus states the actual equipment you used including the type and model number of the equipment.
A block diagram of all the equipment is essential.

IV. Data:
You must include all of the "raw" data taken in the lab book.
You probably should photocopy the data sheet or else include the original data sheet. "Raw" data means the data taken in the lab, not something you calculated later. The raw data is critical because it allows the curious reader to calculate the results independently. So you want to make sure that the data you took during the experiment is neat and readable, so you, or someone else, can make sense of it later.
Absolutely no data can be taken on an individual piece of paper.
Data should be taken in tables with all the columns labeled, units given, and estimated errors.
It's often useful to briefly indicate the experimental set-up with a simple block diagram just above the data table. This is especially useful when you measure something by several different methods.
Each graph must include your name, be titled, dated, and the axes labeled.

V. Calculations:
The calculations take you from the data to the final result. If many similar calculations are involved, just include one sample calculation in detail. Include the errors in raw data and the final result.

VI. Results & Conclusions:
All the results should be stated and summarized in a table or a graph, including the errors. Summarize the results briefly in words and try to make some perceptive comments on what you learned and how to improve the experiment.

The above outline is for a full report and is required only for experiment 8. For all other experiments, only the abstract, a brief explanation of what you did, data and graphs, sample calculation, and results are required.

Grading:
Lab write ups will be graded with a maximum grade of 10. Deductions of 0.5 or 1.0 point will be made for each omission of data, lack of clarity in data or graphs, lack of completeness, etc. Late labs have 3 points deducted for each day the lab is late.

Due date: Lab write ups are due at 4pm in the boxes in the hall before the stairs that lead to the classroom, DeMeritt 152 one week after you did the lab.